1. Field of the Invention
The present invention relates to a red-eye preventing device for preventing a red-eye phenomenon from occurring during flash photography.
1. Description of the Related Art
It has conventionally been pointed out that if flash photography is performed when the luminance of the vicinity of a subject is low, a so-called red-eye phenomenon occurs in which a person or an animal is photographed with the eyes shining in red or gold. It is considered that the red-eye phenomenon is caused by the fact that flash light passing through the pupils of the eyes is intensively reflected by the retina so that the eyes are photographed in red or gold on a film because the color of the blood in the retina is red.
Such a red-eye phenomenon occurs during flash photography, and it is known that it is apt to occur particularly under the following conditions: (1) a case where the vicinity of a subject is dark and the pupils are open; (2) a case where the distance between the flashing part of a flash unit and the optical axis of a photographic lens is close; and (3) a case where the foci of the eyes of a subject are offset (the subject turns away or looks at an object other than a camera).
As a countermeasure against the red-eye phenomenon, Japanese Patent Publication No. Sho 58-48088 discloses the art of preventing the red-eye phenomenon due to flash photography by projecting preliminary illumination light onto a subject prior to execution of the flash photography to reduce the aperture of the pupils of the subject and effecting flashing for photography when the aperture of the pupils is substantially minimized.
Japanese Laid-open Patent Application No. Hei 1-244436 discloses an art which is intended to set a red-eye preventing mode whenever a self-timer mode is set. In the art, after a shutter release button has been pressed all the way down and a self-timer has completed counting time, a flash unit effects preliminary flashing, and after a predetermined time has passed, a shutter release with main flashing is carried out, thereby preventing the red-eye phenomenon due to flash photography.
However, the art of Japanese Patent Publication No. Sho 58-48088 has a number of drawbacks. In this art, to attain a red eye preventing effect, a series of shutter release operations is carried out after the passage of the predetermined time (the light reaction of the eyes) required to substantially close the pupils to the minimum extent. As a result, a photographer is forced to perform an extremely complicated operation, such as the operation of keeping the shutter release button pressed halfway down or keeping a release lock active for a predetermined time by means of a timer circuit. In some cases, a shutter opportunity may be missed because of the release lock.
The art of Japanese Laid-open Patent Application No. Hei 1-244436 also has a number of drawbacks. In this art, the flash unit performs preliminary flashing after the completion of the time counting operation of the self-timer and a photographic operation is carried out when the predetermined time has passed. However, since such a red-eye preventing operation utilizing the preliminary flashing is executed or inhibited in accordance with whether flash photography or normal photography has been selected, variations occur in a time period which passes from the time the self-timer starts counting time until photography is effected. The result is an indication which is extremely difficult to identify. Particularly in the case of a camera which can indicate the time counting operation of its self-timer, since a certain interval passes after an indication of the completion of the time counting operation has been provided, a person to be photographed may believe that photography has already been completed, and change a pose.